Wide range communication and sound attenuation device



y 1964 w. B. WADSWORTH 3,134,456

WIDE RANGE COMMUNICATION AND SOUND ATTENUATION DEVICE Filed Feb. 4, 1960 INVENTOR WM. B. WADSWORTH ATTORNEY United States Patent 3,134,456 WIDE RANGE COMMUNICATION AND SOUND ATTENUATION DEVICE William B. Wadsworth, Concord, Mass, assiguor to David Clark Company Incorporated, Worcester, Mass a corporation of Massachusetts Filed Feb. 4, 1960, Ser. No. 6,661 6 Claims. (Cl. 181-23) Reference is made to copending patent application Serial No. 495,394, filed March 21, 1955, now US. Patent No. 2,946,862, the present invention relating in some respects to an improvement thereon.

The principal object of the present invention relates to the provision of communication means to reach the ears of a person using sound attenuators of the general description of said application and Patent No. 2,899,683, issued August 18, 1959, the present construction being such that a very wide range of specific situations may be accommodated, depending upon the frequencies which are expected to be encountered in a particular application of the device, and the degree of sound attenuation necessary with respect to the quality of communication desired or possible.

It is one of the inherent qualities of the present invention that sound attenuation can be made very eflicient and ambient noises may be kept out to a very high degree, but at the same time the efficiency of the transducer utilized in the sound attenuator is somewhat impaired. However, the novel construction herein presented is very useful for high level surrounding noise situations, particularly including ground crews for jet aircraft and other situations in which the ambient noise level may be very high, but still it being necessary to provide communication with persons using the high etficiency sound attenuators for safety and comfort.

Another illustration of the usefulness of the present invention lies in the use of the sound attenuators to keep out ambient noises when the user is engaged in listening to high fidelity recordings or to an orchestra, particularly those on the air. A bandleader or the like who desires not to be distracted by ambient noises, etc., but who, nevertheless must be aware of cues, or wants to hear just what is going out over the air, finds such a device extremely useful, but in this case the invention is easily adapted to a somewhat lower efficiency in the sound attenuation function with a correspondingly greater ethciency in the sound communication device, i.e., the transducer. Furthermore, the apparatus may be made to accommodate different frequencies which are expected to be encountered in any set situation, and for such functions as sonar analgesics.

Further objects of the invention reside in the provision of a new and improved sound attenuator for application to the ears of the user, said attenuator comprising a rigid shell in which there is provided a relatively large opening receiving an auricle fitting semi or fully rigid plate having removable attaching means to secure it to the shell, covering the opening, said plate also preferably having a central aperture for communication of a transducer in the shell directly to the ear canal and in line therewith, said transducer being connected to said plate by means of a coupler which may be solid and rigid, in which case the communication or efficiency of the transducer is very high, but the efiiciency of the attenuator itself is somewhat impaired; or said coupler may be of soft spongy material or may be of rigid material with holes therethrough leading from the aperture in the plate aforementioned into the interior of the shell past the transducer, in which case the attenuation is made very efficient but the quality of the communication is reduced.

3,134,456 Patented May 26, 1964 Ice Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which:

FIG. 1 is a sectional view illustrating the invention;

FIG. 2 is a view in front elevation, looking in the direction of arrow 2 in FIG. 1;

FIG. 3 is a view in elevation of a form of coupler; and

FIG. 4 is an edge view thereof, partly in section.

In illustrating the present invention, the same has been shown as applied to a commercial device more or less according to the patent above identified, the same comprising a more or less rigid shell generally indicated at 10 which may be in the form of a sphere although it is made preferably spheroidal or ellipsoid in shape. The shell is provided in this case with a relatively large opening which is indicated at 12. This opening is at one side of the shell 10 and provides a rim for the connection thereto of a hard preferably rigid plate 14 which is provided with a circumferential flat rim at 16 adapted to be flatly secured to the rim surrounding the opening 12 as for instance by means of removable fasteners 18 or the like.

Plate 14 is then indented centrally thereof in order to accommodate the ear of the user and it is also preferably ellipsoidal in shape as is opening 12. The main body of the plate is indented as above described to fit the outer ear of the user and is centrally provided with an aperture or hole 20 which is adapted to align with the ear canal. A soft padding or the like at 22 may be utilized for comfort to the user and this padding may be of any kind including a liquid container, soft rubber, vinyl or the like. Incidentally, the shell itself may be substantially filled with soft material as at 24 for the additional reduction of outside sound.

A sound energy apparatus or transducer 26 of commercial type is placed in the shell by being attached to the plate 14. The transducer of course may be provided with the usual cable or wire connection for the phone to some outside source of energy as by the wires indicated at 28. The front portion of the transducer 26 is shown at 30 in FIG. 2.

There is a coupling 32 located between plate 14 and the transducer casing and connecting the same together as is clearly shown in FIG. 1. However, this coupling may take many different forms, depending upon the conditions expected to be encountered in certain applications. The coupling may be made of foam rubber or an aerated latex, vinyl, etc. of any particular required porosity to form a communication between the ear canal and the interior of the shell 10, which communication is not present should the transducer 26 be cemented directly to plate 14. Also, however, the coupling may be of more or less rigid material in the form of a cylinder or ring. This cylinder is provided with a series of more or less radial passages 34 and of course these passages are provided with a cross-sectional area and length according to the circumstances to be encountered, it being recognized that sound waves will pass with varying difficulty through a hollow cylinder of a particular predetermined crosssection and length, depending upon the wave length or frequency thereof, and of course this is easily engineered to suit the problems which may be encountered as to the frequencies expected in any particular situation.

In any event, with the passages between the aperture 20 and the interior of the shell, attenuation of the ear protector is greatly enhanced as will be clear to those skilled in the art, but on the other hand the efficiency of the phone or transducer 26 is somewhat impaired, and therefore the user Will not hear the communicated sound as perfectly as in cases where the transducer is connected directly to the plate 14.

Any variation or proportion between these two effects is achieved by reason of the presence or absence of the coupling 32, the size and length of the holes 34 in the coupling, or the porosity of the coupling if it is made of sponge rubber or the like. Also of course the length of the cylindrical member or coupling 32 may be varied to suit conditions. In any event it will be clear that the degree of communication from the ear canal through hole 20 to the interior of the shell may be any desired degree.

If the transducer is to be used as efiiciently as possible over as wide a range of frequencies as possible, particularly at low frequencies, the porosity of the coupling should be at a minimum. This has a somewhat deleterious effect on the systems attenuation of unwanted ambient noises particularly at low frequencies, but on the other hand the transducer is not required to receive or transmit the lower frequencies and the member 32 acts as a low pass filter to connect the ear canal of the user to the volume of the shell. Hence it will be seen that sound attenuation is traded for improved low frequency response by the action of the coupling 32. That is, if flat response of the transducer is required to 10 cycles at high undisturbed output, on the order of 130 decibels for 0.2 watt input, then the coupling 32 should be small with consequent good communication and relatively lowered attenuation of ambient noise. However, if flat response is needed only above 300 cycles, then considerable coupling is allowable and sound attenuation is high.

The volume of the space between the ear canal and the aperture at 20 is preferably as small as it may be made conveniently, and the plate 14 is made concave to receive the auricle at least in part. The soft seal 22 is thus receptive to the auricle, protects it, and at the same time seals out ambient atmosphere and noise.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. An ear protector comprising a sound attenuator in the form of a substantially rigid shell having a relatively large opening in a side thereof, a substantially rigid plate closing said opening, said plate having a relatively small generally central opening for alignment with the ear canal of the user, and a sound energy transducing apparatus within the sound attenuating shell completely behind the plate, said apparatus being connected to said plate and covering the opening therein at the interior thereof for general alignment of the apparatus with the ear canal of the user, and a coupling between the plate and the apparatus, said coupling securing the apparatus to the plate, said coupling being porous.

2. The ear protector of claim 1 wherein the coupling is also soft.

3. An ear protector comprising a sound attenuator in the form, of a substantially rigid shell having a relatively large opening in a side thereof, a substantially rigid plate closing said opening, said plate having a relatively small generally central opening for alignment with the ear canal of the user, and a sound energy transducing apparatus within the sound attenuating shell completely behind the plate, said apparatus being connected to said plate and covering the opening therein at the interior thereof for general alignment of the apparatus with the ear canal of the user, and a coupling between the plate and the apparatus, said coupling securing the apparatus to the plate, the coupling being substantially rigid and perforated to form passages from the interior of the shell to the opening in the plate.

4. An ear protector comprising a sound attenuator in the form of a substantially rigid shell having a relatively large opening in a side thereof, a substantially rigid plate closing said opening, said plate having a relatively small generally central opening for alignment with the ear canal of the user, and a sound energy transducing apparatus within the sound attenuating shell completely behind the plate, said apparatus being connected to said plate and covering the opening therein at the interior thereof for general alignment of the apparatus with the ear canal I of the user, and a coupling between the plate and the apparatus, said coupling securing the apparatus to the plate, said coupling comprising a cylindrical member surrounding the opening in the plate, said cylindrical member being rigid and formed with passages.

5. The ear protector of claim 4 wherein said passages provide for communication between the opening in the plate and the interior of the shell.

6. An ear protector comprising a sound attenuator in the form of a substantially rigid shell having a relatively large opening in a side thereof, a substantially rigid plate closing said opening, said plate having a relatively small generally central opening for alignment with the ear canal of the user, and a sound energy transducing apparatus within the sound attenuating shell completely behind the plate, said apparatus being connected to said plate and covering the opening therein at the interior thereof for general alignment of the apparatus with the ear canal of the user, and a coupling between the plate and the apparatus, said coupling securing the apparatus to the plate, said coupling comprising a cylindrical member surrounding the opening in the plate, said cylindrical member being porous.

References Cited in the file of this patent UNITED STATES PATENTS 1,616,187 Hart Feb. 1, 1927 1,964,604 Swickard June 26, 1934 2,603,724 Kettler July 15, 1952 2,757,247 Gavreau July 31, 1956 2,890,297 Lehr June 9, 1959 2,946,862 Wadsworth July 26, 1960 

1. AN EAR PROTECTOR COMPRISING A SOUND ATTENUATOR IN THE FORM OF A SUBSTANTIALLY RIGID SHELL HAVING A RELATIVELY LARGE OPENING IN A SIDE THEREOF, A SUBSTANTIALLY RIGID PLATE CLOSING SAID OPENING, SAID PLATE HAVING A RELATIVELY SMALL GENERALLY CENTRAL OPENING FOR ALIGNMENT WITH THE EAR CANAL OF OF THE USER, AND A SOUND ENERGY TRANSDUCING APPARATUS WITHIN THE SOUND ATTENUATING SHELL COMPLETELY BEHIND THE PLATE, SAID APPARATUS BEING CONNECTED TO SAID PLATE AND COVERING THE OPENING THEREIN AT THE INTERIOR THEREOF FOR GENERAL ALIGNMENT OF THE APPARATUS WITH THE EAR CANAL OF THE USER, AND A COUPLING BETWEEN THE PLATE AND THE APPARATUS, SAID COUPLING SECURING THE APPARATUS TO THE PLATE, SAID COUPLING BEING POROUS. 